<b>In a village in Kerala, something extraordinary is happening. The phenomenally high rate of twins born there far exceeds the national average, presenting medical researchers with a mystery that is as yet unsolved. By </b><i>Vinita Bharadwaj</i>.<b> Photographs by Andrew Henderson.</b> Sundays are special days in Rahmath Therambil's home in the village of Kodinji, in the Southern Indian state of Kerala. As well as there being mutton biriyani for dinner, it's the only day of the week when Rahmath, a mother of five and strict disciplinarian, allows her children a day off from revising their schoolwork. Today, however, as her children wake up one after the other, they are told that their plans to play all day will have to be shelved. "We have to go to a medical camp today," she says hurrying them to the bathroom. "But we wanted to play cricket with our friends," says Hussain, her nine-year old son. His twin brother, Hassain, says nothing, but is visibly disappointed. Their younger brother, Usman, who is seven, and sisters Aisha Husna and Fatima Haisu, who are three and also twins, have taken well to the morning's news and rummage through their cupboard to pick brightly coloured clothes and shoes for the outing. On the way to the camp, Hussain persists with more questions but Rahmath is unable to answer him, as she has little information about it or the organisers. All she knows is that the medical camp will collect data to study the phenomenon that has taken Kodinji from a location of relative obscurity to one of absolute curiosity: its incredibly high rate of twins. The latest survey, from December 2009, counted 265 pairs of twins in the village, which is home to about 3,000 families and 13,000 inhabitants. This equates to a twinning rate of about 30 to 35 per 1,000 live births within a radius of about 500 metres. The average in the rest of the country is 8.1 per 1,000 live births. The anomaly has caused a sensation in research circles and generated enormous national and international media interest in Kodinji in the past two years. The number of reporters and researchers arriving unannounced is growing, not always to the delight of the villagers. Tucked away in the lush green northern parts of Kerala, Kodinji is a small village in the Malappuram district. It is a quiet, unassuming village with the noticeable signs of Gulf money pouring in to sustain its people. Small billboards advertising abaya fashion dot the road leading to the village and large multi-storeyed houses with wild gardens of banana and coconut trees function as symbols of prosperity. At the day-long camp, 175 pairs of twins from the village, dressed in their Sunday best, are examined by a team of doctors led by Dr Sribiju, a dermatologist and geriatrician, who goes by one name. The doctors measure the twins' height and weight and note down the vitals of each participant. A dietician then interviews the twins and their parents for a nutritional assessment. One of the examiners, who prefers not to give their name, later says the preliminary observations did not indicate any outward abnormalities in the twins' health and well-being. The camp takes place under the watchful eye of a camera crew from the National Geographic channel. "The high twinning rate is not a new phenomenon in the village," says Dr Sribiju, who first heard about the "twins village" during his tenure at a government hospital in the district. "When I got to know the numbers, I had to investigate it firsthand." He is the self-appointed primary field researcher with the task of determining the causes of twinning among the population. He carries out the research at his own expense and in his spare time, in addition to his full-time responsibilities, which until recently included leading the H1N1 surveillance operations in Calicut International Airport. Progress in his research relies heavily on funding and how much time he can spare. Citing the example of Cândido Godói in Brazil, known as the Twins Capital of the World, Sribiju says Kodinji could not be more different. The Brazilian town, populated almost entirely by German-speaking immigrants, has 38 pairs of blond-haired, blue-eyed twins among about 80 families living within an area of nearly four square kilometres. There are theories that Cândido Godói's twins were the result of experiments by Josef Mengele, the Nazi physician, who notoriously conducted experiments on twins at Auschwitz and was believed to have worked in the area posing as a vet. Kodinji has no such controversy associated with it. "The Brazilian example is strongly believed to be the result of genetic isolation and inbreeding," says Sribiju. "I am not ruling out genetics to be a cause in Kodinji, but I'm also focusing equally on environmental factors." Twins can be monozygotic (identical) or dizygotic (fraternal/non-identical). "Monozygotic twinning is constant throughout the world and counts for about four per 1,000 live births," Sribiju tells me. He presumes the Kodinji births are the result of dizygotic twinning, which occurs when two eggs are independently fertilised by two different sperm cells. To be certain though, he would have to conduct a zygosity test on each set of twins. This would cost him about Rs150,000 (Dh12,000) each time. In developed countries, most dyzygotic twinning is the result of fertility treatment or drugs that stimulate the release of more than one egg. In Kodinji, the mothers deny any intake of drugs, or even the traditional "grandmothers' recipes" said to improve fertility. Unlike in Cândido Godói, consanguineous (blood-related) marriages are not a factor in the Kodinji twin phenomenon. "The majority of the population is Muslim, but the incidences of twinning are present even among the small minority of Hindu families," Sribiju explains. "More importantly, brides who are not originally from Kodinji are giving birth to twins after they move to the village." Rahmath is one of those women. She is originally from Korrad, another village in Malappuram, six kilometres away. Her husband, Kunzalavi, who works away in Umm Al Qawain, married her after his first marriage failed to produce a child in 18 years. She is clueless as to the causes of her two twin pregnancies. "There was no difference between the twin pregnancies and my singleton in between," she says."It's after the births that life is harder. We have more to feed, educate, wed and it's difficult with a single salary even though it is money from the Gulf. But these are God's gifts and we accept it as a blessing." Rahmath manages her household expenses on a monthly budget of Rs3,000 (Dh275). The children's education is free, although she hires a special tutor to come to their home and monitor their schoolwork as she is not literate in English. "Maybe there's something in the soil or the water here," she says shrugging. The soil, water and air are parameters in Dr Sribiju's notes that he intends to investigate and test. There is also the founder effect - the loss of a genetic variation among a localised community - which is believed to explain the Brazilian twins study. While Sribiju isn't ruling this out, he doubts this is the cause. "There could well be a genetic link, but given the number of outsiders entering the community and having twins, I personally think it's very unlikely." Kodinji's twins appear to be largely indifferent to the attention showered on them by foreign visitors and their non-twin neighbours. At the AM Lower Primary School, a government-run institution for grades 1-4, the headmaster Abdussamad (also a twin) summons his school's 4.5 pairs of twins from its 257 students, to face the camera. "One twin from one of the pairs is in another school," he says when quizzed about the "half". "This year we have fewer. If you had come last year, you could have seen eight pairs of twins in the school." A roster of similar-sounding names is read out as Hassain and Hussain, Lubaba and Lubana, Rashid and Rashida, and Muneeb and Mufeeda are marched out in single file into his room. The half twin, a teacher informs the headmaster, cannot be found. The twins stand to attention and stare vacantly as Abdussamad talks about the challenges of educating twins. "Identifying one twin from another is a big problem for the teacher," he says. "We overcome this by making sure they don't sit together in class." All too familiar with the routine of being stared at, the twins return to their classrooms, where their classmates greet them with loud cheers and applause - as if being a twin was an achievement. "Oh, but at that age, it is an achievement," says a 26-year-old villager, Hussain Changnakattir, whose twin brother, Hassain, works as a driver in Qatar. "I understood the twin concept only when I was six years old. Hassain and I felt special and we'd dress up the same. Even now when people see us separately they can't tell us apart, but we have very different personalities." Over time, of course, the novelty wears off, but he says he understands why Kodinji would intrigue outsiders. "I think the overall feeling is one of wanting to understand the causes. We don't want to change God's will, but we are curious by the increase in the number of twins." The village has also become something of a curiosity for the Indian press. Hussain's friend, Rajaskhan, a local reporter with the Malayalam-language newspaper, <i>Chandrika</i>, wrote about the rise in the number of twins in 2001 and since then has assisted numerous TV crews, from Indian as well as international channels, as they arrive to report on Kodinji's "special children". "The oldest twins are 67 years old," says Rajaskhan. "The general feeling is that the spurt in twin births began in the mid-1980s. There were twin births before, but the survival rate was much lower." There are no municipality records available to validate Rajaskhan's information. It is only in recent years that babies have been delivered in the Chammad hospital, about 10 minutes away from Kodinji. "We had a visit from the Centre for Cellular and Molecular Biology in Hyderabad in 2008," says Rajaskhan, "but haven't heard anything from them since then." When I contact GR Chandak, a member of the centre's team who visited Kodinji, he says that plans for formal research are underway. He previously led a team to investigate reports of high twinning rates in another village, in the north, but finds Kodinji far more absorbing. "The north Indian village was more a case of hearsay, with most pairs having only one twin alive," he says. "Kodinji is definitely worth looking into because of the number of live cases." One possibility to be considered is the prescence of a naturally occurring element in Kodinji's environment, something which suppresses oestrogen and increases the FSH (follicle-stimulating hormone) to stimulate multiple ova production, and a factor which would certainly benefit fertility treatment studies. But there is also the suspicion that environmental pollutants are contributing to the phenomenon. Research in Germany dating back to 2004 has suggested that women living in areas where high levels of pollution exist are more likely to have twins. The research proposed that something in toxic waste could suppress oestrogen levels in women, resulting in higher gonadotropin levels of hormones such as FSH, increasing the production of healthy eggs that could become fertilised at the same time - resulting in dizygotic twins. "It's inappropriate for me to speculate on genetic or environmental causes," Chandak says when questioned on this. Until further conclusive findings are obtained, speculation among the locals revolves around naturally-occurring elements being responsible for the effect. "We think it's a blessing, but so far no outsider has come in with a view to settle here in order to have twins," says Rajaskhan, "although if there is more media coverage and some interesting finding, maybe we will have more foreign guests." At home, the day after the camp, Rahmath laughs about all the scientific theories about Kodinji's twins. "We've heard it all. The educated people say we have to understand the twin births so they can help childless couples or make twin pregnancy easier. We don't see anything wrong in co-operating for those reasons." She points to a serene spot about 50 metres away from her house. The site is a quaint grove with a brick structure. "That," she says, "is where Kodinji's spiritual leader, Mampuram Syed Allavi Thangal, used to live 100 years ago. He was very fond of our people. For Kodinji, our twins are the special blessing of his grace. The rest, I don't know."